Does Battletech really not count as a videogame? Mech Warrior Online seems to be going for a complete adaption of the board game so plain Battletech is almost a videogame already.
My personal favorite is probably Chou Soujuu Mecha MG on the DS. The mechs are controlled via touchscreen and d-pad, the pad handles basic movement and the touchscreen manages all the other systems on your mech. Except it's not completely serious so the systems you get can be a puppeteer's cross for moving the arms of your wooden Lincoln mech, a coal oven for powering your steam mech or just a plain old rocket launcher. Some systems can be almost minigames of their own, e.g. a launcher that prompts you to hit buttons in a specific order to fire all the missiles. A turtle mech that has eight segments facing in different directions, each containing a weapon but you can only reload your segments after all of them have been used. A cruise missile launcher that requires inputting a code before the big red "launch" button is revealed.
The game even has 1:1 melee controls and buildings that can be picked up, used as a club, thrown and destroyed. Mission variety is there too with races (where you better take a mech that transforms into a sports car if you want a chance), battles, collecting things like moais from the environment (better bring a mech with hands!) and various fights with special conditions (protect an HQ building, take down all the jammer beacons before they make your mech shut down, "accidentally" destroy a fast food chain in mid-battle as a favor to a friendly restaurant owner).
Only downside is that it has never been released in the West and there can be a lot of dialogue in it.
